Drugging, trafficking and rape – the worst happened in Rochdale all right. The dreadful twist on the typical story of a harrowing crime is that this one was allowed to keep on happening. If the authorities had lacked any clue about the grooming of vulnerable girls, which eventually led to nine convictions this year, that would be one thing. But as the report from the council's safeguarding children board effectively concedes, the warnings were there. As far back as 2007, an official working group identified 50 youngsters at risk of exploitation. Yet such was the guilty men's sense of impunity that, when victims lashed out, causing damage to a taxi and a takeaway, they twice reported them to the police. So what on Earth went wrong?

The failure of the police to pay serious mind to the complaints of youngsters who came to their attention as miscreants is disturbing, but part of a familiar pattern. What is more baffling is the blind eye turned by social services. Thinking was warped by a version of a right-on ethos about respecting the individual decisions of teenagers. An approach that might have been appropriate in the context of a sexual health clinic advising girls with boyfriends was misapplied to a scenario of brainwashing and coercion. Where the police had assumed that this was prostitution, the council made an equally contemptuous and class-bound assumption that these young women from the bottom of the heap had freely made "a lifestyle choice". This is a shrunken, atomistic notion of decision, which disregards intimidation and peer pressure. It is a no-such-thing-as-society view. For a social services department to adopt it is a bitter irony indeed.

Another element may have been ethnicity. Caveats are important here because, in discussion of grooming, there is plenty of prejudice and no reliable statistics. We know that the overwhelming majority of sex offenders are white, but it does not follow that the same is true in every criminal sub-category. Different cultures do give rise to different violent pathologies. The fondness of white Britain for alcohol, to take one example, gives rise to forms of thuggery which would be unheard of in Muslim communities. Arranged marriages and low female employment in Muslim Britain are indicative of – at the very least – different attitudes to gender. There is no proven link between these and the (mercifully rare) cases of the Rochdale type that we have witnessed among South Asian Muslims. But such a connection cannot be ruled out a priori.

If social services feared to tread to avoid causing offence, and perhaps complicating wider work within the Pakistani community, then that has proved a terrible error. For giving offence is as nothing compared with the grotesque offences that eventually transpired.